Sol'Kanar the Tainted is a mythic Legendary Creature — Elemental Demon card from Dominaria United Promos (PDMU), collector number 219p. Current market price: $0.38 (foil $0.51), TCGplayer market prices via Scryfall.
At the beginning of your end step, choose one that hasn't been chosen — • Draw a card. • Each opponent loses 2 life and you gain 2 life. • Sol'Kanar deals 3 damage to up to one other target creature or planeswalker. • Exile Sol'Kanar, then return it to the battlefield under an opponent's control.